stewart



July 27, 1926.

A. c. sTrwAR-r THERMOSTATIC CONTROL MEANS FOR WATER HEATERS Filed Oct. 26, 1923 Fig. l.

n du v NVENTOR ,4P/'red Cf Sfe wari'.'

` ATTORNEY v fFig. 2 isv a section on linef2-2 in 1.

Patented July ZlSJZ.v

- UNITED srar y'rmiRiiros'rii'r1c con'rnoyniiiniins noaivnrna enzimas; j

This invention relates yto automa-ticycon-y trol of Water heaters of the storage typein which a body :of `water` in a suitablel tank is maintained at an approximately constant temperature by automaticy control or" the gas 'supply thereto. kind'it has ybeen usual to thermostatically control the gas supplyonly. with the. result" that when the desired temperature of the 'Water'l'ias been obtained and the gas supply is automatically'shut ofi, cold atmospheric air continues to pass into the 'ivaterheater and as it Vis not'thenl Warmedby combustion gas it exercises a Cooling action on'the healtf er',` resulting in considerable loss cfheat which has to be compensated for. byvcombustion of a VCorrespondingly increased. amount offgas.

The main object of heater by cutting 'off or controlling the air supplyk ysiniultaneously andv correspondingly with the gas supply so as to prevent the heat loss abovereferred lto and provide vfor manif mum ,eihciency of the heater. n f The accompanying dra-Wings illustratemy invention. 'f f v V"'Fig.' 1y isl a vertical 4section of a Water heater provided with my improved control-y lingme'ans.

Fig. 3 sjan enlarged vertical sectioii'jof thegas and air Acontrolling means.l Y Fig. 4 is a corresponding section showing a modification.V

1' The Waterheater shown in the drawing` comprises a Water' container, tankforre# ceptacle 1 formed for example as Aa `vertical cylinder provided 'with 'y inlet ymeans 2 vfor f cold Water and outlet means forl'iot'vvarer. and mounted in a suitable' or usual manner.. The tank 1 is enclosed in an outer casing l yspaced from the tank to form a passage "13 for hot gases'and ,provided at its upper endl with an' outlet lfors'uch `gasesv and 'at its lower end lwith* a combustion ,chamber 6', formed for `example inl a'. base '7 on which V lthe tank 1 and vcasing` 4L( are supported.y Said In an,` apparatusofV this the present invention yis to increase the eiiiciencyofl `the Water` ffii-meatyffhaboaem of amie i and Said tankfis provided with an inner tubel 10 eX- y tendingupwardly from its bottom and opening at the 'lower lend` into the combustiony chamber and closedat its upper end. -A bar, t

rod, or other thermostatic control member-12 isl'connected at its upper end to the tube 1()` and is corinectedjat' its lo'iver end to the valve means 'lijn' controlling,"th'egsupply of fgas and.

air `v`as hereinafter described. `SJaidftubev 10. and rod l2 constitute a thermos-tatie imitery teiidingv'ertically W'ithinftank 1 so asfto be The rod 'or-memberf12"consists oflmaterial of diii'erent'eiipansibility from thatf'o` the material ofthe inner 'tube 10,`i'orexample,l

sai'dinember`12may begof iron, [the inner tube beingbtbrassfsothat-byireason of the greater 'thermal' expansion coeiiicient of brassl as compared4 with iron auf-increase of temperaturein,tlieineinberslOand l2due, i

to or accompanying anvincrease of tempera`' ture in ,the body otwatergintlieheater tank' 1 causes,arelativev elongation tot member 1U lsubjected to the temperature of ysaid tank. f 'i fio.

upward f* movement `ofloiver end ofrod On the lo'vverfportionof'member 12 is mounted'avalve*membervconsisting for ex* y,ample of a plateordiskltadapted vto coop-"Vy '.erate 'v'vith the circular valvese'ats 15 andl.k Valve seat `15`-is formed onthe bottom of a tubular member '.17 extendingy upwardly from thebottoinof thecombustion chamber y 6,-"the linterior otsaid tubular member y17vr forming theinixing chamber 11, and com# `18, communicating With, theV outer air through an 'opening 19.; A top member `formed as' aplateor ,fdisk 21 e'itendsover 3 niunicatingV at its'lower 'end' with the spacel j Within the'base vmember 7 underthe controlv of the valveidisk 14, said space',` indicated v at the tubular member llfloiutisspacedfthere-A "from by lspacers such" -as -vvires 22 yso ,aste .y

leave a constricte'd annular -slot'23 through whichv the mixed" gas an'dair can escape into the combustion chamber 6 for combustion therein. "The:thermostatic' `controly rod l12 extends freely throughy the topv plate 21 andA is"attaclied Vto the valve diskgll which is adapted to close to' any fdesired extent', the

lower/end ofthe tubularf member 17', said valve: `disk being preferably adjustablef` onthe control memberl2for example by screwing thereon' as indicated. A gas supply duct l indicatedat 25 is adapted for communication With `the gas supply ipe 'indicated at 26 and communicates Wit a ,vertical pasJ 'j f f i sage 27 in a member 28 surrounding the control rod 12 and having the valve seat 16 at its lower end, the valve seats 15 and 16 being for example in the same plane so that' a substantially flat disk 14 may cooperate with both of them simultaneously..

The combustion chamber 6 opens through passages 30 into the space 13 between the tank 1 and jacket 8.

Suitable means may be provided for igniting the mixtureas it issues into combustion chamber 6 for example, a pilot flame pipe 32 extending from the` gas duct aforesaid, and opening into the combustion chamber 6 adjacent to theoutlet 23 y'tor themixture. In order to enable access to the pilot flame, for example for ignition thereof, an opening 85 may be provided lin the Wall of the base 7, said opening being normally closed by plug 36 (see Fig. 1,).

In case it isv desired to admit auxiliary air into the combustiony chamber 6 for ensuring combustion of the, mixture admitted thereto, suitable, auxiliary air passages may be provided, controlled -by thermostatic means above described `so yas to controly the admission of such auxiliary air in correspondence With, the admission of gas and mixture. For thisv purpose auxiliary air passages or inlets 38 may be provided communicating with the combustion chamber 6 andl controlled by valve members 39 connected to the thermostatic controllingrod 12, being attached for exampleto the valve plate or disk 14 aforesaid, soi as to-move and operate simultaneouslyithereivith to control admission of air to -theauxiliary air ports 88,. in correspondence vvith the admission of the air to the. air port or passage formed Within the tubular member 17.

The operation is as follows:

Gras being supplied to theiheater by means oli pipe 26y and lWater being supplied by means of pipe 2 so that the interior` of,- lzhe tank 1 is full of Water.. and the pilotV flame being ignited the operation of 'the burner startsv by reason et the fact that When the tank 1 and contents thereof are. cold, the valvemember 111L is-depressed due to therelative contraction of the thermostatic control memberlO at this time and gas will tlierefore flow into the mixing chamber 11V within tubular member 17- and air will flow,

into,y such chamber from thel inlet openingy between the valve-seat 15.and the valve member 14.y The resulting mixture of combustible gas and air flows out through thev outlet 25 and is ignited by the pilot flame and the,A

resulting hot combustion gases passv out through .the passages and upwardly in the space 13 around the tank 1, thereby heating the Water in the tank. then the tank and the contents thereotl are at av sutiiciently high temperature the consequent elongation oi' the thermostatic control member 1() causes the, valve member 14 to be raised so as to close the air and gas inlets to a greater or less extent, andas the supply of air is shut ofi in correspondence With the supply of gas there Will be no cold air flowingin Contact with the tankat any time and the maximum conservationof heat is secured. In caseauxiliary air is used asin the embodiment shown in Fig. 4 such auxiliary air is shut oii at the same time as the mixe` 4 ing air so that in that ease. also there is no possibility of iiorv ot cold air through the heater whenv the main burner,l is not in operation. It Will be understood-thatthe device acts. as a regulating means as vvell as a shut orf means, so that the lsupply .oit gas and air is gradually decreased as the temperature of the tank rises, and gradually increasedA as the temperature of the tank falls.

lVhat I claim is- 1. In a Water heater of thestorage type, a tank for containing Water, burner means provided with ay mixing chamber, means for admitting` gas and air to said `mixing chainber, means fory admitting auxiliary air to said burner means independently of said mixing chamber, a single valve member operable to control the means forv admittingv gas and air to the mixing-chamber and. also the means for admitting auxiliary air, and a thermostatically controlled member extending adjacent said tank and; adapted to be heated by the water thereinandconnected to said valve member to control, the

same. f f

2. In a Water heater of they storageA type, autank for containing'v Water, burnerl means provided With a cylindrical mixing chamber, meansv deiining. any annular oriice for the admission of gasto said. mixing chamber, means defining: an` annular orifice concentric and exterior to, saidyiirst-named orifice for the admission of air to said mixing..chamber, and thermostatically controlled means` ALFRED v C. STEIVARI. 

